1. Field of the Invention
The present invention relates to horsepower and efficiency indication and monitoring systems, and more particularly, to automatically programmed apparatus for continuously, electronically supervising and controlling operating parameters of a prime mover so as to enable increased fuel efficiency, and reduced cost of operation for "Optimized Reduced Speed Operation."
2. Description of the Prior Art
Numerous situations exist where a shaft is rotated by an appropriate drive mechanism to perform useful work. Exemplary of the same are electric power plants, industrial machine drive systems, propeller-driven ships and the like. In all of these systems, and in fact in any system in which a powered prime mover causes the power rotation of a driving shaft, it is extremely important to effectively monitor the horsepower being transmitted through the shaft as well as the overall efficiency of the system assembly. Furthermore, it is important to maintain the speed and power being transmitted from the prime mover for the optimum fuel consumption versus power output characteristics to effect a fuel conservation program, or a "Reduced Speed" operation for low fuel rate consumption when conditions dictate slower travel.
In connection with propeller-driven ships, it is extremely important that monitoring equipment simply, yet effectively provide accurate and continuous indications of the horsepower being transmitted through the ship's propeller shafts in order to enable the ship's operating personnel to obtain the optimum performance for developing the maximum output with the least consumption of fuel. While this may be a relatively minor task in connection with small pleasure craft, it becomes a substantial undertaking in connection with large commercial ships such as ocean liners, freighters and tankers. In these latter instances, measurements must be undertaken from one or more engines capable of producing many thousand horsepower and transmitting such power through propeller shafts often many city blocks long and weighing many tons. Yet, these measurements must be accurate, reliable and rapid.
In view of the increasing scarcity of fuel for driving engines such as those used on propeller-driven ships, it is also important to be able to monitor the operating parameters of the ship's engines and to automatically control torque and RPM so as to provide the lowest "Specific Fuel Rate" value comparable to the maximum power output at the minimum fuel consumption level. A small change in propeller RPM causes a relatively greater change in SHP power and a significant variation in fuel consumption.
On both ship and shore based prime mover power equipment, a propulsion panel is generally employed for operating and controlling the speed and direction of the prime mover, whether it be diesel, steam turbine, or gas turbine (jet engine). The propulsion panel may perform its function by penumatic logic, hydraulic logic, electrical control, electro-mechanical control or micro-processor control.
In the past, propulsion panel control has been regulated directly and manually by an operator in response to the operator's observations of engine operation. In order to maximize or optimize fuel efficiency, it is required that some provision be provided to more accurately regulate engine operation consistent with actual, on-going measurements of torque and RPM in consideration of weather conditions, schedules, tides, docking cargo and fuel costs. The need for such automated control is apparent from an appreciation of the fact that the most engine efficient power output is not achieved merely by selecting maximum torque and maximum RPM, but is dependent upon combinations of both torque and RPM values, taken together with actual measurements of fuel consumption.
In my prior U.S. Pat. Nos. 3,274,826; 3,960,012; and 3,972,224, systems are disclosed for providing rapid and accurate measurement of shaft horsepower and efficiency. However, the prior art does not show systems for developing both on-off and variable feedback control of shaft rotational speed or both on-off and variable feedback control of torque for affecting the highest efficiency and fuel economy of operation.